Preheat oven to 350ºF. Butter and flour two 9-inch cake pans. Line bottoms with rounds of parchment paper.

Whisk together flour, salt, baking powder and baking soda in a bowl.

Using electric mixer, beat butter in large bowl until fluffy. Gradually add sugar, beating until blended, scraping down sides of bowl. Beat in lemon juice, zest, then 1 egg at a time. Continue to beat until well blended.

Bake cakes until tester inserted in the centre comes out clean, about 45 minutes. Cool cakes in pans on racks.

TO ASSEMBLE: Make White Chocolate Cream Cheese Frosting. Turn first layer of cake on platter. Peel off parchment. Spread with 1 cup frosting. Place second layer on top. Remove parchment. Frost remainder of sides and top. Keep in refrigerator until ready to serve.